Field of the Invention
Aspects of the present invention generally relate to assembly equipment that performs assembly operation with two robot arms having aligning holding hands.
Description of the Related Art
In industry, a number of pieces of assembly equipment that perform assembly operation using robot arms have been used. In recent years, there has been a demand for assembly equipment that achieves assembly operation using robot arms, instead of manually performing assembly operation. In contrast, in manual assembly performed in production factories, a human cell production system has been introduced in which conveyors are removed and a person directly conveys workpieces and assembles a plurality of kinds of parts and complementary materials to the workpieces.
There is a new cell production system called a “machine cell production system” that enhances productivity of an operator by combining manpower and assembly equipment.
From such a background, there is a demand for assembly equipment that can assemble a plurality of parts and complementary materials to a workpiece only in the assembly equipment in order to perform assembly using robot arms instead of manual assembly.
Japanese Patent Laid-Open No. 2010-105106 (hereinafter referred to as “Patent Document 1”) proposes a production system that can assemble a plurality of parts and complementary materials to a workpiece to enhance working efficiency.
The production system of Patent Document 1 comprises a pair of manipulators equipped with hands for holding a part of an assembled part, an assembly stage serving as an assembly position for two parts, and a control device for operating the manipulators. The manipulators are arranged such that working areas of the hands overlap to form an overlapping working area. The assembly stage is provided in the overlapping working area.
However, the related art disclosed in Patent Document 1 has the following problems.
First, a number of detachment and conveying operations are sometimes performed during assembly.
It is necessary to perform a workpiece conveying and attaching operation of conveying a workpiece from a supply position to a predetermined position on the assembly stage by the robot arm and attaching the workpiece to the assembly stage and a workpiece removing and conveying operation of removing the workpiece from the assembly stage and conveying the workpiece to an eject position. Since assembly operation is performed with the workpiece being held on the assembly stage, working efficiency is reduced.
Further, it is necessary to hold, in the hands, tooling such as a coating device and a screwdriver and to attach and detach the tooling in response to a holding operation and a release operation. This also reduces working efficiency.
Secondly, a sufficient degree of freedom in assembly needed to an assembly operation, such as a coating operation, is sometimes not ensured. Since the operation is performed with the workpiece being fixed on the assembly stage, the posture of the workpiece is limited and this makes it difficult to perform assembly with a high degree of freedom. When the assembly stage is used, a fixing jig is frequently used in combination with the assembly stage, and this increases the production cost.